Data transmitting apparatus

ABSTRACT

A data transmitting apparatus which can reduce the load of the work of checking the AV data by the operator. AV data reproduced by a CH library (230) is recorded in a first cache (340) and second cache (350) via a distributor (330). At this time, the check sum regarding the AV data as the numerical value data is found in the calculating unit inside the CM library (230) and sent to a cache processing unit (310) via a library processing unit (210). The AV data recorded in said two caches are respectively subjected to test reproduction and the check sums are found by the calculating unit in each cache similar to the above. Where these check sums are all equal, it is decided that the transfer of the AV data was suitably carried out. Also, the AV data having a lower error rate between the AV data reproduced by the two caches is selected by the main switcher (400) and transmitted.

This application is a continuation of application Ser. No. 08/750,206filed Mar. 7, 1997.

TECHNICAL FIELD

The present invention relates to a data transmitting apparatus whichtemporarily transfers AV data comprising audio data and video datastored in a library etc. to a predetermined recording apparatus andperforms the transmission of that AV data using that transferred data.

BACKGROUND ART

In a broadcasting station, broadcast program data, for examplecommercials(CN) programs, etc. is usually stored in a library. Thenecessary broadcast program data is successively selected, reproduced,and transmitted from that library according to a broadcast schedule.This series of processing is controlled and managed by a control meanscalled a library management system (LMS). Using this LMS, a libraryhaving data on an enormous number of CM programs recorded in a verylarge number of recording media, for example, several thousand videocassette tapes, is managed and suitably used for broadcasting CMprograms.

However, usually, in a broadcasting station, to prevent any interruptionof the broadcast, the system is configured so that important apparatusessuch as said library are duplicated, and even if one breaks down,operation by the other is possible. However, such duplex provisionsrequire double the cost. In particular, duplication of large scaleapparatus such as said library for CM programs has a great economicinfluence.

Further, In such a multiplexed library system, it is necessary to selectone series of data for actual broadcasting from the plurality ofbroadcast program data output. Normally, this selection is performed bythe switching operator viewing the monitor to check the quality of thevideo and audio at the main switcher, but this work places a heavyburden on the switching operator.

DISCLOSURE OF THE INVENTION

The present invention has as its object to provide such a datatransmitting apparatus for transmitting broadcast program data such asfor CM programs which can ensure the same extent of reliability as thatby the duplex provisions of a library by a simpler configuration, inother words, a lower cost. Further, it has as its object the provisionof an apparatus which can eliminate or reduce the checking of the AVdata by the operator and thereby lighten the work load.

In recent years, AV data is also being digitalized and broadcast programdata is being recorded as digital data in a library etc. in many cases.If the broadcast program data is digital data, techniques such as errordetection codes (error correction codes) which are often used in datatransmission etc. can be applied. Namely, by comparing the errordetection codes produced with respect to AV data before and after thetransfer, whether or not the AV data are equivalent can be checked.Further, it is possible the check the quality of the AV data by usingthe error rate and therefore upgrade the reliability.

Accordingly, a data transmitting apparatus of the present inventioncomprises a reproducing means for storing AV data comprised of at leastone of video data and audio data and reproducing the stored AV data, atemporary recording means for temporarily recording the AV datareproduced by said reproducing means, a control means for controllingsaid reproducing means and said temporary recording means, a first errorstate detecting means for detecting an error state of the AV datareproduced by said reproducing means and outputting a first errordetection signal, a second error state detecting means for detecting anerror state of the AV data reproduced by said temporary recording meansand outputting a second error detection signal, a transfer checkingmeans for deciding that the transfer of the AV data from saidreproducing means to said temporary recording means was suitably carriedout when said first error detection signal and said second errordetection signal are equal, and a data transmitting means forreproducing and transmitting the AV data suitably transferred to andrecorded in said temporary recording means.

Preferably, when said transfer checking means decides that said firsterror detection signal and said second error detection signal aredifferent, said control means controls said reproducing means and saidtemporary recording means so as to again carry out the transfer of saidAV data from said reproducing means to said temporary recording means.

Specifically, it further comprises an input means for inputtingtransmission scheduling data showing the transmission schedule of saidAV data, and said control means controls said reproducing means and saidtemporary recording means based on said transmission scheduling data sothat said data is transferred from said reproducing means to saidtemporary recording means before the scheduled time of broadcast of saidAV data.

More preferably, it comprises a first transmission line connecting saidreproducing means and said temporary recording means and a secondtransmission line connecting the first error state detecting means andthe transfer checking means, and the second error state detecting meansand the transfer checking means each, on the first transmission linebeing transmitted fixed length data packets having a first data portionincluding the video data for each horizontal line's worth of the videodata and a second data portion including the audio data corresponding tothe video data and predetermined auxiliary data, and on the secondtransmission line being transmitted at least said first error detectionsignal and said second error detection signal.

Specifically, said first transmission line is a transmission line whichcan transmit said AV data by a first transmission rate, and said secondtransmission line is a transmission line which can transmit said firsterror detection signal and said second error detection signal at asecond transmission rate slower than said first transmission rate.

More preferably, said temporary recording means comprises a plurality ofrecording means, said control means controls said reproducing means andsaid temporary recording means so that the same data reproduced by saidreproducing means is recorded in each of said plurality of recordingmeans, said second error detecting means detects said error state foreach of the AV data reproduced by said plurality of recording means andoutputs a plurality of second error detection signals, and said transferchecking means decides that the transfer of the AV data from saidreproducing means to said temporary recording means has been suitablyperformed when the first error detection signal and the plurality ofsecond error detection signals are all equal.

Preferably, said data transmitting means comprises a data selectingmeans for selecting and transmitting one series of AV data from aplurality of series of AV data reproduced by said plurality of recordingmeans under the control of said control means.

More preferably, said data selecting means comprises an error ratedetecting means for detecting the error rates of each of the AV datareproduced by the plurality of recording means and the AV data with thelowest error rate is selected based on the results of detection of saiderror rate detecting means.

In such a data transmitting apparatus of the present invention, thelibrary means storing a plurality of types of AV data preliminarilyreproduces and outputs the AV data scheduled to be transmitted andrecords it in the temporary recording means. At this time, apredetermined error detection code is found in the first code computingmeans for the AV data reproduced in the library means. Also, the AV datarecorded in the temporary recording means is immediately subjected totest reproduction and a predetermined error detection code the same asthat of said first code computing means is found by the second codecomputing means. Then, the error detection code found by said first codecomputing means and the error detection code found by said second codecomputing means are compared by the transfer check means. Where they areequal, it is decided that the transfer of the AV data from said librarymeans to said temporary recording means was suitably carried out. Thesuitably transferred AV data is suitably reproduced and transmitted inaccordance with the request.

BRIEF DESCRIPTION OF DRAWINGS

The above object and features of the present invention will become moreapparent from the following description with reference to theaccompanying drawings, wherein:

FIG. 1 is a block diagram of the configuration of a data transmittingapparatus of a first embodiment of the present invention;

FIG. 2 is a block diagram of the configuration of a data transmittingapparatus of a second embodiment of the present invention;

FIG. 3 is a block diagram of the configuration of a library of the datatransmitting apparatus shown in FIG. 2;

FIG. 4A is a view for explaining the format of AV data processed by thedata transmitting apparatus shown in FIG. 2;

FIG. 4B is a view for explaining the transfer packets of AV data of theformat shown in FIG. 4A;

FIG. 5 is a block diagram of the configuration of a first cache shown inFIG. 2;

FIG. 6 is a flow chart for explaining the operation of the transfer ofAV data inside the data transmitting apparatus shown in FIG. 2; and

FIG. 7 is a flow chart for explaining the operation of the transmissionof AV data by the data transmitting apparatus shown in FIG. 2.

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment

A first embodiment of the data transmitting apparatus of the presentinvention will be explained referring to FIG. 1.

The data transmitting apparatus of the present embodiment is acommercial (CM) program transmitting apparatus used in the broadcastingstation. The apparatus copies the CM programs scheduled to betransmitted among a large amount of CM programs stored in the library ina temporary recording unit called a "cache" and performs the actualtransmitting by using the CM program data copied in that cache as thetransmission data.

FIG. 1 is a block diagram of the configuration of a data transmittingapparatus of the present embodiment.

A data transmitting apparatus 900 comprises a library 910, a temporaryrecording device 920, and a switcher 930.

The library 910 comprises a large amount of video tapes on which CMprograms are stored, a reproducing unit for reproducing from the videotapes, and a media changer for suitably automatically exchanging andsetting in the reproducing unit the video tapes and reproduces andoutputs the requested CM program data.

The temporary recording device 920 comprises a first cache 920a and asecond cache 920b and records the CM program data input from the library910 on these two caches in the same way. In accordance with thebroadcast schedule, the recorded CM program data is simultaneouslyreproduced at these two caches and output to the switcher 930. Note thatthe first cache 920a and the second cache 920b are each separate hardmagnetic disk apparatuses.

The switcher 930 selects and transmits one series of data from the twoidentical series of CM program data input from the temporary recordingapparatus 920. The selection of the transmission data at this time isperformed by the operator checking the two series of CM program datainput on a monitor. However, so long as no breakdown etc. occurs, thetwo series of CM program data are input suitably and either one of theseries of data can be freely selected.

In the data transmitting apparatus 900, the data scheduled to betransmitted for about the next one week are transferred to the temporarystorage apparatus 920 from the CM program data stored in the library910. The actual transmission of the CM program data is performed usingthe AV data recorded in the temporary recording apparatus 920.

By using this configuration, the recording apparatuses are duplicatedfor the AV data scheduled to be transmitted for a while, so even if onerecording apparatus broke down, it was possible to transmit the CMprogram data using the other recording apparatus immediately andtherefore secure the same level of reliability as with provision of twolibraries as mentioned above. Further, with such a configuration of adata transmitting apparatus, the system can be configured cheaper thanthe case of provision of two of the libraries themselves.

Second Embodiment

However, in the data transmitting apparatus of the first embodiment, theoperator had to check the AV data which was transferred and reproduced.For example, when CM program data was transferred from the library tothe temporary recording apparatus, it was necessary to check if thetransfer had been performed suitably. The operator had to reproduce theAV data recorded in the temporary recording apparatus and check thequality of the picture and sound on a monitor etc. Therefore, in thedata transmitting apparatus of the first embodiment, it was not possibleto lighten the work load of the manager or operator.

An explanation will be made of a data transmitting apparatus able tosolve problems and lighten the work load of the operator as a secondembodiment referring to FIG. 2 to FIG. 7.

The data transmitting apparatus of the second embodiment is also CMprogram transmitting apparatus using at broadcasting station the same asthe first embodiment.

FIG. 2 is a block diagram of the configuration of the data transmittingapparatus.

The data transmitting apparatus 100 comprises a library unit 200, acache unit 300, a main switcher 400, and an input unit 450.

First, an explanation will be made of the configuration and function ofthe respective portions.

First, the configuration and function of the portions of the libraryunit 200 will be explained.

The library unit 200 comprises a library processing unit 210, a librarycontroller 220, and a CM library 230.

The library processing unit 210 is constituted by a general purposecomputer etc. and controls the library unit 200 as a whole.

The library processing unit 210 controls the CM library 230 through thelibrary controller 220 so as to read the data of the predetermined CMprogram from video tapes 500-i (i=1 to m) stored in the CM library 230based on instructions for copying the CM program data input from thecache processing unit 310 of the cache unit 300 mentioned later andoutput the same to the cache unit 300.

More specifically, it outputs information of the video tape on which thedata of the desired CM program is recorded and a signal instructing thereproduction thereof to the library controller 220. Also, it receives asits input the error detection code obtained at the reproduction of theCM program data from the library controller 220 and outputs the same tothe cache processing unit 310 of the cache unit 300.

The library controller 220 actually controls the specific operation ofthe CM library 230 based on the instructions input from the libraryprocessing unit 210. More specifically, it instructs the identificationnumber of the video tape to be reproduced, the location for reproductionin that tape, and the reproducing unit for reproducing to the CM library230 and executes the reproduction of the desired CM program. Also, itoutputs the error detection code at the time of the reproduction, outputfrom the CM library 230, to the library processing unit 210.

The CM library 230 selects and reproduces the cassette tape in which thedesired CM program are recorded from a large number of cassette tapes inwhich CM programs are stored, outputs the desired programs to the cacheunit 300, and, at the same time, outputs the error detection code at thetime of reproduction to the library controller 220.

A detailed explanation will be made of the configuration of the CMlibrary 230 by referring to FIG. 3.

The CM library 230 comprises a media changer 231, n number ofreproducing units 232-j (j=1 to n), a calculating unit 233, and aswitcher 234 and further comprises m number of video tapes 500-i (i=1 tom) in which the CM programs are recorded and stored.

The video tapes 500-i (i=1 to m) are recording medium in which the CMprogram data is actually recorded. In the video tapes 500-1, the CMprogram data is recorded in the form of digital data. Note that, usuallyone CM library 230 will handle about 500 to 1000 video tapes. Also,these video tapes are stored at predetermined positions of rackshapedstorage cabinets and are automatically set in the reproducing units232-j and removed from the reproducing units 232-i by the media changer231 mentioned later.

The media changer 231 selects a video tape 500-i (i=1 to m) in which adesired CH program is recorded from m number of video tapes 500-1 to500-m stored in the CM library 230 and sets that video tape 500-i in apredetermined reproducing unit 232-j (j=1 to n). The media changer 231comprises a tape transporting unit 231b for actually transporting thetape and setting it in the reproducing unit 232-j and a media changercontrol unit 231a for controlling the tape transporting unit 231b. Theinformation of the video tape 500-j selected and the reproducing unit232-j in which it is set is informed from the library controller 220 tothe media changer control unit 231a. Further, when the reproduction ofthe set video tape 500-i ends, the tape transporting unit 231b removesthe video tape 500-i from the reproducing unit 232-j and returns thesame to the original predetermined storage position.

The n number of reproducing units 232-1 to 232-n each have set in themvideo tapes 500-i by the media changer 231. Based on an instruction fromthe library controller 220, the video tape 500-i is reproduced from thereproducing units 232-j and that program data is output to thecalculating unit 233 and the switcher 234.

The calculating unit 233 regards the reproduced CM program data as usualbinary data and sequentially adds it to calculate the check sum. Thecalculated check sum is output to the library controller 220. In thisembodiment, the 15 frames AV data of the AV data of the format mentionedlater are all added to find the check sum. That is, one check sum isfound and output for every 15 frames.

The switcher 234 selects one of the n number of reproducing units 232-1to 232-n based on the instruction from the library controller 220 andoutputs this as the reproduced AV data from the CM library 230.

Here, an explanation will be made of the format of the program data atthe time of reproduction at the library unit 200 and transfer to thecache unit 300 referring to FIG. 4.

The data transmitting apparatus 100 of the present embodiment transfersthe AV data based on the serial data interface (SDI) system. The SDIsystem is a format standardized as SMPTE-295M by the SMPTE (Society ofMotion Picture and Television Engineering).

FIG. 4A is a view of the configuration of a frame of the AV data (videosignal) of the SDI system, while FIG. 4B is a view of the configurationof a transfer packet of the SDI system.

The frame of a video signal of the SDI system, as shown in FIG. 4A andFIG. 4B, is constructed of 525 or 625 lines in the vertical direction(hereinafter, the specific number of the system which has 625 lines inthe vertical direction is showed in parentheses) and 10 bits×1724 (1716)words per line in the horizontal direction.

In each line, the first word to the fourth word of the line show the endof the active video portion ACV and are used for separating code EAV(End of Active Video) separating the active video portion ACV and theancillary data portion ANC. The 276 (268) words from the fifth word tothe 280th (272) word are used as the ancillary data portion ANC which isused for the supplementary data and the audio data etc. The four wordsfrom the 281st (273) word to the 284th (276) word show the start of theactive video portion ACV and are used for separating code SAV (Start ofActive Video) separating the active video portion ACV and the ancillaryportion ANC. The 1440 words from the 285th (277) word to the 1724th(1716) word are used as the active video portion ACV for transmittingthe video signal etc.

Further, as shown in FIG. 4A, in the vertical direction, the nine (24)lines from the first line to the ninth (24) line are used as thevertical blanking portion VBK. The 10 lines from the 10th line to the19th line is used as the optional blanking portion OBK. The 244 (288)lines from the 20th (25) line to the 263rd (312) line are used as theactive video portion ACV₁ of the first field. The active video portionACV, of the first field includes the video signal of the first field.

The nine (25) lines from the 264th (313) line to the 272nd (337) lineare used as the vertical blanking portion VBK. The 10 lines from the273rd line to the 282nd line is used as the optional blanking portionOBK. The 243 (288) lines from the 283rd (338) line to the 526th (625)line are used as the active video portion ACV₂ of the second field. Theactive video portion ACV₂ of the second field includes the video signalof the second field.

The video signal of the SDI system of this frame configuration isconverted into transmission signals of a serial format of for example270 Mbps, and sent and received among the portions of the datatransmitting apparatus 100 converted into transmission signals of aserial format of for example 270 Mbps.

Further, as explained above, the calculating unit 233 calculates thecheck sum for every 15 frames worth of data of the SDI data of thisconfiguration.

Next, an explanation will be made of the configuration and function ofthe cache unit 300.

The cache unit 300 shown in FIG. 2 comprises a cache processing unit310, a cache controller 320, distributor 330, a first cache 340, and asecond cache 350.

The cache processing unit 310 is constituted by a general purposecomputer etc. and controls the entire cache unit 300 so as to suitablyrecord and transmit the CM program data input from the library unit 200.In particular, according to the present invention, it controls the eachof portions of the cache unit 300 so that the transfer of the CM programdata from the library unit 200 to the cache unit 300 and thetransmission of the CM program data from the cache unit 300 to the mainswitcher 400 are suitably carried out.

More specifically, the cache processing unit 300 controls each of theportions so that the cache unit 300 carries out the followingoperations:

Further, it records the CM program data input from the library unit 200via the distributor 330 in the first cache 340 and the second cache 350.

Next, it decides whether or not the transfer of the CM program data fromthe library unit 200 to the cache unit 300 was suitable.

For this purpose, the cache processing unit 310 first causes a testreproduction of the recorded CM program data and makes the computingunits in the first cache 340 and the second cache 350 calculate a checksum when regarding the respectively test-reproduced CM program data asnumerical value data. Also, the cache processing unit 310 reads thecheck sums and determines whether or not they coincide with the checksum input from the library unit 200. Where the check sum of the resultof even one of the test reproductions of the first cache 340 or thesecond cache 350 does not coincide with the check sum input from thelibrary unit 200, it decides that the transfer of the CM program datafrom the library unit 200 to the cache unit 300 was not suitably carriedout and outputs a signal requesting a second transfer to the libraryprocessing unit 210 of the library unit 200.

Further, the cache processing unit 310 performs selection as to which CMprogram data recorded in the cache of the first cache 340 or the secondcache 350 should be transmitted when transmitting CM program datarecorded In the cache unit 300. The cache processing unit 310simultaneously sends reproduction instructions to the first cache 340and the second cache 350 when a request for transmission of CM programdata is input. Then, at that reproduction, it instructs the mainswitcher 400 to compare the reproduction error rates input from each ofthe first cache 340 and the second cache 350 via the cache controller320 and select and transmit the CM program data having a lower errorrate.

The cache controller 320 controls the specific operations of each of theportions actually constituting the cache unit 300 based on theinstructions input from the cache processing unit 310.

More specifically, it instructs the recording and reproduction of theinput data, calculation of the check sum, and detection of the errorrate to the first cache 340 and the second cache 350. Also, it outputsthe check sum and error rate obtained at the first cache 340 and thesecond cache 350 to the cache processing unit 310. Further, it outputs aselection signal indicating which cache output of the first cache 340 orthe second cache 350 should be transmitted to the main switcher 400.

The distributor 330 divides the CM program data which is input from theCM library 230 of the library unit 200 into two signals and inputs themto both of the first cache 340 and the second cache 350. By this,exactly the same signal is input to the first cache 340 and the secondcache 350.

The first cache 340 and the second cache 350 temporarily record the CMprogram data scheduled to be transmitted and input from the library 200through the distributor 330. The first cache 340 comprises a recordingunit 341 and a calculating unit 342 as shown in FIG. 5. While not shown,the second cache 350 has the same configuration as the first cache 340and comprises a recording unit 351 and calculating unit 352.

The first cache 340 and the second cache 350 first receive as input theCM program data actually scheduled to be transmitted from the libraryunit 200 via the distributor 330 and record it in the recording unit 341and the recording unit 351, The exact same CM program data is recordedin these two recording units.

The recorded CM program data is immediately test reproduced based on theinstructions from the cache controller 320. At the time of this testreproduction, the reproduced CM program data is regarded as numericaldata and the calculating units 342 and 352 calculate the check sums forthese reproduced CM program data. The obtained check sums are inputthrough the cache controller 320 to the cache processing unit 310 wherethey are compared against a check sum input from the library unit 200 soas to check if the transferred data is suitable or not.

When the transfer is suitable, the data recorded in the recording units341 and 352 of the first cache 340 and the second cache 350 areconsidered valid as the CM program data for transmitting.

When a reproduction instruction for transmitting the transmittable CMprogram data is input from the cache controller 320, the recording units341 and 351 reproduce the recorded desired CM program data and output itto the main switcher 400. At this time, the first cache 340 and thesecond cache 350 detect the reproduction error rate of everypredetermined series of data and output the same to the cache controller320.

Note that, either of the first cache 340 or the second cache 350 acts asthe main cache and the other acts as the sub-cache. Usually, at the timeof the start-up of the data transmitting apparatus 100, the first cache340 becomes the main cache and the second cache 350 becomes thesub-cache, but if predetermined conditions occur, this relationshipbetween the main and sub cache may be suitably switched.

Finally, the configuration and function of the main switcher 400 and theinput unit 450 will be explained.

The main switcher 400 receives as its inputs the CM program data outputfrom the first cache 340 or the second cache 350 and selects andtransmits either of them based on the selection signal from the cachecontroller 320.

The input unit 450 is an input means for inputting the CM programtransmission schedule and transmission requests to the data transmittingapparatus 100. The input unit 450 may be a direct input means such as akeyboard or may be an interface means which receives instructions fromother computer or control apparatus etc. and may be of any specificconfiguration.

Next, an explanation will be made of the operation of the datatransmitting apparatus 100 referring to FIG. 6 and FIG. 7. Note that inFIG. 6 and FIG. 7, the solid lines show the flow of the processing andthe broken lines show the flow of the data.

First, an explanation will be made of the operation for transferring theCM program data to be transmitted from the library unit to the cacheunit 300 with reference to FIG. 6.

FIG. 6 is a flow chart showing the flow of processing in each portion inthe processing for transferring the transmission use CM program datafrom the library unit 200 to the cache unit 300.

First, when a CM program transmission schedule is input by an input unit450 such as a keyboard to the cache processing unit 310 of the cacheunit 300 (step S10), the cache processing unit 310 extracts the AV datato be transferred from the library unit 200 to the cache unit 300 as atransmittable state based on the transmission schedule and produces aspecific transfer instruction. Also, at this time, it resets the counterfor counting the times of transfer k to 0 (step S11).

Further, it inputs the thus produced transfer instruction to the libraryprocessing unit 210 of the library unit 200 and starts the transfer ofthe desired CM program data. At this time, it increases the number oftransfers k by 1 (step S12).

The library processing unit 210 controls the library CM library 230 viathe library controller 220 and executes the transfer instruction of therequested CM program data (step S13). Namely, the media changer 231 setsthe video tape 500-i in which the requested CM program data is recordedin the predetermined reproducing unit 232-J, reproduces that video tape500-i in the reproducing unit 232-J, and outputs the result to the cacheunit 300 via the switcher 234 (step S14). At this time, the calculatingunit 233 calculates the check sum regarding the reproduced CM programdata as numerical value data and outputs it to the library processingunit 210 through the library controller 220.

The cache unit 300 records the CM program data input from the libraryunit 200 in both of the first cache 340 and the second cache 350 (stepS14).

After the transfer of this CM program data ends, the check sumscalculated along with the reproduction of the data are transferred fromthe library processing unit 210 to the cache processing unit 310 (stepS16). Note that this transfer may be performed in a package after theend of the transfer of the CM program data as in this embodiment or maybe successively performed in parallel with the transfer of the CMprogram data.

Further, the cache unit 300 test reproduces the CM program data recordedin the first cache 340 and the second cache 350 (step S17). The cachecalculating units 342 and 352 calculate the check sums by the samemethod as the CM library 230 (step S18).

Then, the cache processing unit 310 compares the check sums obtained bysaid test reproduction and the check sum input from the libraryprocessing unit 210 of the library unit 200. When they are all equal, itis decided that the transfer from the library unit 200 to the cache unit300 was suitably carried out (step S19) and the series of transferprocessings is normally ended (step S20). Due to this, CM program dataable to be immediately transmitted in accordance with transmissionrequests are prepared in the first cache 340 and the second cache 350.

On the other hand, where even one of the check sum of the first cache340 or the second cache 350 differs from the check sum input from thelibrary processing unit 210, it is decided that the transfer was notsuitably carried out (step S19). Further, it finds if the number oftransfers k of the transmission requested CM program data is less orequal than a predetermined certain number K (step S21). When less thanthe predetermined number K, it instructs the copying of the CM programdata once again to the library unit 200. That is, it repeats theprocessing from step S12. Further, when the number of transfers kbecomes larger than the predetermined number of transfers K (step S21),the series of processing is abnormally ended considering that some sortof trouble has occurred in the data transmitting apparatus 100 (stepS22). Note that in the present embodiment K is made 3. That is, thetransfer is attempted three times and when it is not suitably carriedout in these three times transfers the transfer processing is abnormallyended.

Next, an explanation will be given of the operation of transmission ofthe CM program data for which the preparations for transmission werecompleted referring to FIG. 7.

FIG. 7 is a flow chart showing the flow of processing for each portionin the processing for transmitting the transmission use CM program datarecorded in the cache unit 300.

In the state where the preparations for transmission of the CM programdata have been completed as mentioned above, when a request fortransmission of the CM program data is input from the input unit 450,the cache processing unit 310 controls the first cache 340 and thesecond cache 350 through the cache controller 320 so as to execute thetransmission of the CM program data (step. S31). That is, the recordingunit 341 of the first cache 340 and the recording unit 351 of the secondcache 350 simultaneously reproduce the CM program data (steps S32, 33)and transmit them through the main switcher 400. At the time of thisdata transmission, the first cache 340 and the second cache 350 detectthe reproduction error rate for each predetermined unit of data at thesame time as the reproduction of the CM program data and output the samethrough the cache controller 320 to the cache processing unit 310 (stepsS34, 35). The cache processing unit 310 compares the error rates inputfrom the two caches (step S36) and outputs a selected signal to the mainswitch 400 so as to select the output of the cache with the lower, thatis, the smaller error rate (step S37). Until the reproduction of the CMprogram data at the first cache 340 and the second cache 350 is ended(step S38), the each predetermined unit of reproduction error rates areconstantly monitored, and the selection processing of the transmissiondata is repeated. The end of reproduction of the CM program data endsthe series of processing for data transmission (step S39).

In this way, the data transmitting apparatus 100, first, when the CMprogram data is transferred from the library unit 200 to the cache unit300, decides whether or not the transfer was suitably carried out byusing the check sums. Accordingly, it becomes unnecessary for a humanoperator to view the transferred CM program on a monitor to check thesuitability of the transfer and thus the efficiency of the work fortransmission of CM programs is improved.

Also, it is possible to detect the error rate for the CM program datarespectively reproduced by the first cache 340 and the second cache 350and select and transmit the CM program data having a smaller error rateby the main switcher 400. Therefore the efficiency becomes very high incomparison with a method wherein the transmission data is constantlychecked by a human operator to detect deterioration of the image qualityand the outputs of the two systems are switched manually.

Further, the data transmitting apparatus 100 usually transfers the errordetection code through the general use interface connecting thecomputers or computers and terminal equipment etc. separate from thetransmission line for transferring the AV data. Accordingly, even if thedata transfer system is one which cannot transfer the error detectioncodes together with the packet of AV data, it is possible to suitablytransfer the error detection codes and check the transferred data. Thepresent invention is particularly effective for such a system.

Note that, the data transmitting apparatus of the present invention isnot restricted to the present embodiment. Various modifications arepossible.

For example, in the library unit 200 and the cache unit 300 of thepresent embodiment, as means for controlling the processing, the libraryprocessing unit 210 and the cache processing unit 310 are provided asthe highest layer. As the means for actually performing the control ofthe constituent units, the library controller 220 and the cachecontroller 320 were provided. However, these control means are notrestricted only to this configuration. For example, it is also possibleif the processing units and the controller are integrally constituted orall of them are constituted by a single arithmetic processing apparatus.Note, usually, in specific control, the processing is dependent onhardware and the amount of processing is large, and in the control ofthe higher units, there is a lot of processing, for example,communication with the other apparatuses or further higher apparatuses.Therefore the configuration of the present embodiment is suitable.

Also, the reproducing unit 232 of the CM library 230 of the presentembodiment was constituted by n number of reproducing units 232-1 to232-n, but the number is not restricted to this. Any configuration canbe adopted in accordance with the usage of the data transmittingapparatus 100. For example, when the frequency of transfer of theprogram data from the library unit 200 to the cache unit 300 is small,it is also possible to constitute the reproducing unit 232 by a singlereproducing apparatus. However, in a case when the frequency of use ishigh, for example, program data is sequentially and successivelytransferred, a configuration providing two or more reproducing units asin the present embodiment and reducing the overhead time of exchange ofthe video tapes 500-i is preferred.

Also, in that CM library 230, a configuration providing only onecalculating unit 233 for finding the check sum for the n number ofreproducing units 232-1 to 232-n is adopted in the present embodiment.Of course, a configuration providing one for each of the reproducingunits 232 can be adopted too.

Further, the CM library 230 of the present embodiment comprises aconfiguration having only the output of one system as the output, but aconfiguration having outputs of a plurality of systems can be adoptedtoo. At this time, the switcher 234 of the CM library 230 becomes amatrix switcher means and the reproducing unit 232 desirably isconstituted by a further larger number of reproduction apparatuses. Adata transmitting apparatus of such a configuration is also amodification of the present embodiment. It is clear that the gist of thepresent invention is applied without change.

Also, the reproduction apparatus 232 of the CM library 230 acts also asa recording apparatus for recording the program data in the video tape500 in many cases. There is no problem if a configuration using such arecording and reproducing apparatus is adopted.

Also, the recording media to be used in the CM library 230 is notrestricted to a cassette tape. Any recording medium can be used. Forexample, it is also possible to use usual magnetic tape, hard magneticdisks, magneto-optic disks, digital video disk apparatuses, etc.

Moreover, the recording media constituting the first cache 340 and thesecond cache 350 of the cache unit 300 are not restricted to hardmagnetic disk devices. It is also possible to use a usual magnetic tape,magneto-optic disk, digital video disk device, or semiconductorrecording apparatus.

Also, in the present embodiment, the suitability of the reproduction andtransfer of the CH program data from the library unit 200 to the cacheunit 300 and the suitability of the CM program data from the cache unit300 to the main switcher 400 were determined using a check sum regardingthat CM program data as numerical value data. However, the invention isnot restricted to this. Any suitable procedure can be adopted. Forexample, various types of error detection codes, error correction codes,etc. such as a CRC (cyclic redundancy check) or the like which isusually used in transmission etc. can be applied.

Also, in the present embodiment, a system of applying the datatransmitting apparatus of the present invention to the transmission ofCM programs was explained as an example, but it is clear that theinvention can be applied to the transmission of any AV data other thanCM programs. Also, the data is not restricted to AV data having audiodata and video data. It is also possible if the data has only audio dataor only video data and also usual digital data is possible.

According to the data transmitting apparatus of the present invention,the check of the transferred or reproduced AV data can be automaticallycarried out, and therefore the check of the AV data by the operator canbe eliminated or reduced and the work load can be reduced.

INDUSTRIAL APPLICABILITY

The data transmitting apparatus of the present invention can be used forvarious AV data transmitting apparatuses used in broadcasting stationsetc. such as for example automatic transmitting apparatuses for CMprograms.

    ______________________________________                                        LIST OF REFERENCES                                                            ______________________________________                                                100  data transmitting apparatus                                              200  library unit                                                             210  library processing unit                                                  220  library controller                                                       230  CM library                                                               231  media changer                                                            232  reproducing unit                                                         233  calculating unit                                                         234  switcher                                                                 300  cache unit                                                               310  cache processing unit                                                    320  cache controller                                                         330  distributor                                                              340  first cache                                                              341  recording unit                                                           342  calculating unit                                                         350  second cache                                                             351  recording unit                                                           352  calculating unit                                                         400  main switcher                                                            450  input unit                                                               500  video tape                                                       ______________________________________                                    

What is claimed is:
 1. A data transmitting apparatus comprisingreproducing means for reproducing stored data including audio and/orvideo data (AV data), a plurality of temporary recording means fortemporarily recording said data reproduced by said reproducing means,and data transmitting means for reproducing said data temporarilyrecorded in said plurality of temporary recording means and transmittingsaid reproduced data,the apparatus further comprising:first error statedetecting means for detecting an error state for said reproduced datawhen said data is reproduced from said reproducing means and outputtinga first error detection signal; second error state detecting means fordetecting an error state for said reproduced data reproduced by saiddata transmitting means and outputting a second error detection signal;and comparing means for comparing said first error detection signal andsaid second error detection signal, such that said reproducing meansreproduces said stored data again when said first error detection signaland said second error detection signal are different in said comparingmeans.
 2. The data transmitting apparatus as set forth in claim 1,wherein when said first error detection signal and said second errordetection signal are different, as determined by said comparing means,said reproducing means and said temporary recording means are controlledso as to carry out the transfer of said data from said reproducing meansto said temporary recording means again.
 3. The data transmittingapparatus as set forth in claim 1, whereinsaid data transmitting meanscomprises data selecting means for selecting and transmitting oneportion of the reproduced data from one of said data reproduced fromsaid plurality of recording means.
 4. The data transmitting apparatus asset forth in claim 3, whereinsaid data selecting means comprises errorrate detecting means for detecting error rates of each of the datareproduced from each of the plurality of recording means to select thedata with the lowest detected error rate.
 5. The data transmittingapparatus as set for in claim 4, further comprising:input means forinputting transmission scheduling data representing the transmissionschedule of said data, and wherein said reproducing means and saidtemporary recording means are controlled based on said transmissionscheduling data so that said data is transferred from said reproducingmeans to said temporary recording means before a scheduled time ofbroadcast of said data.